Boyut etkisi çimento esaslı kompozitlerden yapılan kolon düz döşeme birleşimlerinin zımbalama kayma davranışı

Engineering cementitious composite material (ECC) with adding two kind of synthetic fibers (polyvinyl alcohol 6-12mm and polypropylene12mm) are used to search the effect on the punching shear behavior of flat plate column connection. Totally twelve slabs are poured and tested, nine of ECC slabs are dividing for three groups each group have three panels depending on the kind of fiber (PVA 6, PVA 12 and PP12mm) and then compared these ECC panels with three control slabs of normal concrete. The thickness of the slabs in each group is varying (50, 60, and 80 mm). In order to investigate the effect of the size of the panels on the punching shear of flat slabs, with fixing for the rest dimensions (500 × 500 mm). All slabs are reinforced with same reinforcement ratio 0.12. The results of test showed that the slabs made from ECC with fibers give less deformation from the normal concrete. This is due to the ability of the ECC to capture crack growth and crack is widening. The addition of fiber leads to a reduction in deformities at all loading stages and especially after initial first crack, also enhancement the final load carried by the flat slab. Fibers not only defer the deformations of the diagonally cracks within the panels, but also shifting the punching shear failure to gradually and ductile shear failure crack patterns. Also the test shown decreasing in shear stress with increasing the slab thickness. But the nominal shear strength is increased with the slab thickness increasing. The ECC PVA 6 show greatest enhancement for nominal shear strength ranging between 25-43% more than the normal concrete. Key Words: Column slab connection, PVA and PP fibers reinforced concrete, conventional steel reinforcement, punching shear, size effect